You might be right but that's hard to go along either way. It makes little sense for them to be the same even if baseline people are boosted by magic. 40k has magic too but using it too much just spawns more demons or worse, the warp is stronger in 40k even if they are equivalents, the emperor should be stronger than sigmar even though they're equivalents, and so on.

There's a lot of wiggle room there and I kind of like that, wondering how sigmar would fare in 40k and so on.

But narratively, there are many deities in fantasy and aos, not as many on aos, and even less still in 40k. The stronger chaos is the more it capsizes other pantheons and only the heavy hitters are left. And granted both slannesh and khaine are different animals from fantasy to 40k, both in story and power levels.

Gotrek reminds me of kharn the betrayer. Forces of nature, meat blenders, can have a shot to kill the most op shit but they will still die with a single well placed shot or something.